1. Field of the Invention
The present invention relates to a treating process for solidifying a radioactive waste and more particularly to solidification by sintering crud (crud being an abbreviation for "Chalk River unidentified deposit" which has been found by the Chalk River nuclear laboratory in Canada and refers to the corroded products containing radio-activated Beta and Gamma nuclear species) formed in the cooling water system of a reactor.
2. Description of the Prior Art
In order to store for a long period of time, or dispose of a radioactive waste generated from a nuclear power plant etc., it is necessary to minimize the leakage and diffusion of radioactive substances into the environment. It is for this purpose that it has been generally attempted to transform the radioactive waste into a stable solidified body. Prior treating processes for solidifying the radioactive waste include mainly a cement-solidifying process, asphalt-solidifying process, plastics-solidifying process, glass-melt solidifying process and the like. However, the cement-solidifying process is low in its volume reducing ability. The asphalt-solidifying process uses a melted asphalt having a high temperature upon solidification, so that there are drawbacks that there happens to be a danger of fire and the water proofness of the solidified bodies is not sufficient. The plastics-solidifying process cannot be applied to a high level of radioactive waste. The glass-melt solidifying process needs to effect the treatment at a high temperature, so that a part of radioactive substances is volatilized and further, the volume reducing ability is poor.
In a primary cooling water system of a reactor in a nuclear power plant, oxides of iron, cobalt and the like or corroded products created on and scaled off from instruments or pipes of the primary cooling water system in a system for feeding water into a reactor are flowed into the reactor, together with the cooling water and stick to and deposit upon a surface of the fuel rod and are subsequently irradiated with neutrons on a surface of the fuel rod to form a radioactivated crud. This radioactivated deposited crud is dissolved off or scaled off and flows out of the reactor together with the cooling water and sticks on the system instruments, pipes and the like, so that a dosage rate of these instruments, pipes and the like is raised, whereby the operators, or the maintaining or controlling workers are exposed to the radioactivated crud. Therefore, the crud should be solidified to minimize such exposure. However, an adequate solidifying treatment has not been heretofore established with respect to a medium level or high level of radioactive waste in a slurry form, such as crud, so that such waste is stored in a tank as a crud slurry and it has been demanded that the process for treating the crud is found as early as possible.